Irrigation is pouring water to the soil using proper methods and in proper times as required by the plant growth as a result of insufficient rain. The success of irrigation depends on the selection of the most proper irrigation method as per the conditions and planning, projecting, establishing and operating the irrigation system necessary for that method.
Irrigation methods are divided into two groups according to the features related with deliver and application of water on soil. These are surface irrigation and pressure irrigation methods.
In surface irrigation systems water is moving over the land by simple gravity flow in order to wet it and to infiltrate into the soil. With the application of water to the land surface does not always accomplish the intended purpose. Much of this water is lost due to evaporation, run-off, percolation passed the root zone and so on. They can be subdivided into furrow, border strip or basin irrigation. Surface irrigation systems are typically less efficient in applying water than pressure irrigation methods. Many are situated on lower lands with heavier soils and, therefore, tend to be more affected by water logging and soil salinity if adequate drainage is not provided. Surface systems tend to be labour-intensive. Another disadvantage of surface irrigation methods is the difficulty in applying light, frequent irrigations early and late in the growing season of several crops.
In the second method, pressure irrigation method, the water is given to soil by using closed pipe systems with an additional energy or a drawing effect. It is of two types one is sprinkler irrigation and other is drip irrigation.
In sprinkler irrigation the water is given to the soil surface under a little pressure and through laterally located sprinkler heads spraying thin drops. But there are many disadvantages associated with this kind of irrigation. Some of them are more usage of water compared to drip irrigation high cost of power, wind interferes with the distribution pattern and nozzle clogging.
In drip irrigation system, irrigation water necessary for plant growth is applied around the root of plant in the form of drops through specially designed tools named emitters/drippers located on or inside the lateral pipe. Each dripper/emitter, orifice supplies a measured, precisely controlled uniform application of water, nutrients, and other required growth substances directly into the root zone of the plant. The discharge flow rate of the emitters varies according to the need of the crop, types of soil and local weather condition.
There are multiple types of irrigation drippers/emitters. Emitters are classified into groups based on how their design type and the method they use to regulate pressure. A very simple emitter is created by drilling a very small hole in a pipe. However, a hole alone does not work well. Unless the hole is extremely small, the water tends to forcefully shoot out of it like a tiny fire nozzle and way too much water comes out. More importantly, there is little uniformity of flow when using a simple hole.
The emitters can be installed on the pipe and act as small throttles, assuring that a uniform rate of flow is emitted. Some are built into the pipe or tubing, others attach to it using a barb or threads. The emitter reduces and regulates the amount of water discharged.
Other categories of drip emitters include pressure compensated and non-pressure compensated. Pressure compensated emitters are designed to discharge water at a very uniform rate under a wide range of water pressure which is more expensive than the Non pressure compensated (Non PC) emitters and also not suitable for all types of drip irrigation systems.
Emitting pipe is very important component in drip irrigation system which distributes the water through emitter to plant. Performance of emitting pipe is totally depended on emitters and supplier's technical engineer is choosing emitter discharge during the design of any field/farm. Therefore accurate discharge emitter is the key component in entire drip irrigation system.
Generally the emitter comprises of a pressure reduction channel which is known as “labyrinth channel” more commonly known as “labyrinth”. The labyrinth generally comprises a tortuous “obstacle” flow path that generates turbulence in water flowing in the labyrinth to reduce water pressure and discharge of water by the emitter.
Emitter clogging is one of the most important factors that affect the performances on drip irrigation systems. Emitter clogging, which is formed in a short time due to irrigation systems' running under an inadequate pressure or owing to water quality, not only negatively influences uniformity of water distribution but also causes inadequate irrigation. The small openings of the emitter can be easily clogged by soil particles, organic matter, bacterial slime, algae or chemical precipitates effects water and fertilizer uniformity, increase maintenance costs, and cause crop damage.
There are several drip irrigation systems including emitters are available in the art. Some of them are discussed herein below for reference.
The U.S. Pat. No. 7,108,205 discloses a drip irrigation system employing parallel adjacent flow paths in wherein a drip irrigation tube having a plurality of sequentially placed emitters formed on an interior wall of the tube. Each emitter employs a series of parallel flow paths axially positioned along the tube to provide for closer proximity of inlet ports to discharge chambers thereby providing for closer spacing of the emitters. Overlapping of the inlet portion of the sequentially positioned emitters with the outlet portion of any preceding emitter provides for even more compact positioning of the emitters along the tube.
Another US Pat. publication No. 20100096478 discloses a non-clogging non-pressure compensated drip emitter that utilizes one or more filters or one or more inwardly offset filters that have an inlet that projects inwardly toward a centerline of the hollow cylindrical emitter body and a labyrinth having only turbulent transfer zones after water enters the labyrinth, wherein the labyrinth couples the filter(s) or inwardly offset filter(s) to the pool. Prevents clogging by eliminating dead transfer zones where sediment can accumulate where no turbulence exists. Also prevents clogging when the filter is positioned downward as the inwardly offset filter rises above any sediment when the emitter is positioned in the field in this downward orientation. Also prevents clogging flat filter configurations that have filters offset radially, i.e., redundant filters per emitter.
U.S. Pat. No 6,945,476 discloses to a self-compensated drip irrigation emitter. The emitter of this invention is capable of always supplying a substantially constant flow within a range of pressures of a fluid flowing in a pipe, from very low to very high pressures. Furthermore, the emitter of the invention has such characteristics as to prevent any accidental and undesired clogging thereof by sediments or debris.
Disadvantages of Prior Art Drip Irrigation Systems Including Emitters are as Follow:
1. Available Single emitter for different discharge through multi outlet has following disadvantages:                These types of emitters have single discharge from single outlet and double discharge from two outlets.        These types of emitter have multi oriented inserting option.        These types of emitters have separate flow path for single discharge which can allow clogging of one outlet.        These emitters require two drilling within one emitter for higher or multiple discharge which increases complexicity of drilling vis-à-vis more initial cost. These types of emitters have high installation and maintenance cost.        
2. Available non-clogging, non-pressure compensated drip emitter utilizes one or more filters to prevent clogging in the labyrinth. The water that enters the emitter also contains suspended soil particles which are not accurately filtered by the provided filters. This causes clogging into the labyrinth.
3. Available drip irrigation system uses Pressure compensated type emitter has higher initial investment costs and marginally higher operating costs compared to systems using non-pressure compensated emitters. To overcome the problem of clogging greater water filtration is generally required for these emitters.
4. The available emitters has to inserted unidirectional, which reduces the efficacy of the production of emitting pipes.
From above it is clear that the forgoing prior art emitters have various problems, mostly dealing with water pressure and water clogging in the labyrinth.
So, In view of the above, it is apparent that there is need of an improved portable Non pressure compensated, Non clogging, multi flow emitter with common labyrinth, which overcomes all the above-mentioned drawbacks.